JPH1120770A - Chain roller structure of chain driven vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase displacement and shock absorption easily and make a structure simple. SOLUTION: A chain roller 22 which supports a chain when a rear wheel is lowered to a specified limit or more is installed on a body frame 2 to provide an elastically deformable structure of the chain roller 22. A hard rubber or hard resin roller 22a provided with multiple lotus root-shaped mass removing holes 29 is deformed elastically at the mass removing holes 29 when a chain pressing load is applied to them so as to relieve a tension on the chain. Also a shock absorbing mechanism is provided between a body frame and a roller support member so as to relieve the tension. In addition, the roller support member formed with elastic materials is mounted on the body frame side so as to relieve the tension.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chain roller structure for a chain drive vehicle such as a motorcycle.

[0002]

2. Description of the Related Art The chain roller structure of a motorcycle includes:
For example, Japanese Unexamined Utility Model Publication No. 60-60388 discloses an apparatus for preventing slack in a drive chain of a motorcycle. According to FIG. 2 of the publication, a swing arm 16 having one end pivotally supported on a vehicle body is known. A roller 15 is rotatably provided at the other end of the arm, and a fixed arm 21 is welded to the vehicle body below the rocking arm 16, and the upper part of an adjustment bolt 23 perpendicular to the rocking arm 16 is rocked on the fixed arm 21. The roller 15 is mounted so as to be in contact with the moving arm 16, and the roller 15 pushes up the drive chain 1 to prevent the drive chain 1 from sagging.

[0003]

Since the roller 15 generally uses a hard resin in consideration of abrasion resistance, the roller 15 has poor shock absorbing power. A motorcycle called an off-road motorcycle sometimes hops (large vertical movement) when decelerating on a rough road such as a mountain road that is not paved. At this time, the tension of the chain 1 repeatedly acts in the driving direction and the deceleration direction, and a higher chain tension is generated than in normal traveling. The cycle of the chain tension is about 15 times per second.

When the lower chain (in the deceleration direction) is pulled and the chain contacts the roller 15 disposed on the lower side, a force for contracting the rear suspension is generated. The intermittent shock chain tension adversely affects the rear suspension, and may deteriorate ride comfort.

Accordingly, an object of the present invention is to provide an inexpensive chain roller structure having a large displacement and shock absorbing ability, a simple structure, and a low cost.

[0006]

In order to achieve the above object, a first aspect of the present invention is to mount a swing arm on a body frame so as to be vertically movable, and to mount a rear wheel rotatably on a rear portion of the swing arm. In a chain drive vehicle in which wheels are driven by an engine arranged in front of the swing arm via a chain, a chain roller supporting the chain is attached to the body frame side when the rear wheel drops by a certain amount or more, and the chain roller is elastically mounted. The structure is such that it is transformed into

[0007] Since the chain roller is configured to be elastically deformed, the displacement and shock absorbing performance can be easily enhanced, and the structure is simple and the number of parts can be reduced.

According to a second aspect of the present invention, the chain roller is a hard rubber or a hard resin roller having a plurality of lightening holes. By forming a plurality of lightening holes in a solid rubber or hard resin solid roller, the deformation performance is dramatically improved. Since the structure is simple, cost can be reduced.

According to a third aspect of the present invention, the chain roller has a wear-resistant material attached to the outer periphery of the soft resin. When the chain hits the chain roller, the soft resin bends to reduce the chain tension. On the other hand, the wear-resistant material prevents wear of the outer peripheral portion. Excessive tension can be reduced and durability can be improved.

A fourth aspect of the present invention is an engine in which a swing arm is mounted on a vehicle body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is disposed in front of the swing arm via a chain. In a chain driven vehicle that is driven, a roller support member is vertically movably mounted on the vehicle body frame side, a buffer mechanism is provided between the vehicle body frame side and the roller support member, and the rear wheel descends on the roller support member by a certain amount or more. And a chain roller for supporting the chain when the chain is mounted.

A large displacement can be absorbed by mounting the roller supporting member on the vehicle body frame side so as to be vertically movable, and the shock absorbing performance can be enhanced by providing the roller supporting member with a shock absorbing mechanism. The number can be reduced.

A fifth aspect of the present invention is an engine in which a swing arm is mounted on a vehicle body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is disposed in front of the swing arm via a chain. In a chain driven vehicle that is driven, a roller supporting member made of an elastic material is attached to the body frame side, and a chain roller that supports the chain when the rear wheel descends by a certain amount or more is attached to the roller supporting member. And

Since the roller supporting member is made of an elastic material,
Displacement and shock absorption performance can be improved, and the structure is simple, and the number of parts can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of a motorcycle according to the present invention. In the motorcycle 1, a handle post 4 and a front fork 5 are attached to a head pipe 3 at a front end of a body frame 2 so as to be steerable. 6, an engine 7 is provided at a lower center portion of the body frame 2, a fuel tank 8 and a seat 9 are provided at an upper portion, and a swing arm 11 is vertically movably extended from a lower rear portion of the body frame 2.
A rear wheel 12 is mounted on a rear portion of the swing arm 11, and a rear sprocket 13 mounted on the rear wheel 12 is driven by a driving sprocket 15 on the engine side via a chain 14. 20 is the body frame 2
Is a chain roller structure provided at the lower rear part.

FIG. 2 is a cross-sectional plan view of the chain roller structure according to the present invention. The chain roller structure 20 includes a washer 21, a chain roller 22, a washer 23, and a mounting bolt 24. It is attached to an arm bolt 18 for attaching the link arm 17 with an attachment bolt 24.

The chain roller 22 has a hole 25 at the center of the hard resin roller 22a, and recesses 28, 28 for accommodating bearings 26, 27 are provided at both ends of the hole 25. A lightening hole 29 is formed on the outer peripheral side, and bearings 26,
27 is a roller with a bearing in which a steel collar 31 is mounted between the bearings 26 and 27.

FIG. 3 is a sectional view taken along line 3-3 of FIG.
10 lightening holes 2 concentrically arranged with 5 at substantially equal pitch
9 ... (... indicates a plurality, the same applies hereinafter). That is, the lightening holes 29...
Are arranged on a circle centered at.

FIGS. 4A to 4C are front views of the chain roller according to the present invention, and the operation of the chain roller 22 for absorbing the impact of the chain 14 will be described. (A)
Indicates a state in which the chain 14 is separated from the chain roller 22. During normal traveling, the chain 14 is separated from the chain roller 22. At this time, the tension due to the power is applied to the chain 14a above the center of the rear sprocket 13 (FIG. 1) and the center of the drive sprocket 15 (FIG. 1).
(FIG. 1). Therefore, the chain 14 does not cause a bad influence on the riding comfort.

FIG. 2B shows a state in which the chain 14 is the chain roller 2.
2 shows a state in which the chain 14 slightly touches the chain roller 22 when the rear wheel 12 (FIG. 1) moves downward slightly. Since the chain 14 is constantly moving as shown, the chain roller 22 rotates as shown. The chain roller 22 is guided by a small deflection and rotation, and the tension of the chain 14 is properly maintained.

FIG. 3C shows that the chain 14 is the chain roller 2.
2 shows a state in which the chain 14 is pressed, and the rear wheel 12 moves further downward, whereby the chain 14 strongly hits the chain roller 22. At that moment, the chain guide roller 22 is greatly recessed. Therefore, the impact is not absorbed and the tension of the chain 14 does not become excessive.

That is, on a rough road, the rear wheel 12 of the motorcycle 1 in FIG. 1 moves largely up and down. When the rear wheel 12 descends, the surface layer of the chain roller 22 bends at the moment from the state of (a) to the state of (b). Next, the rear wheel 12 is further lowered, and the lightening holes 29 are bent (c).
State. Since the chain 14 is always moving,
To prevent the tension from becoming excessive while rotating.

FIG. 5 is a graph showing the relationship between the load and the amount of deflection of the chain roller. The horizontal axis represents the load P, and the vertical axis represents the amount of deflection δ of the chain roller. Here, the amount of deflection is the amount of depression of the roller. The dashed line is a comparative example in which a material is a hard resin and a solid roller is used. The solid line is made of hard resin and adopts a roller with a plurality of lightening holes like a lotus.
This is an example. The broken line is a modified example employing a roller made of urethane foam and having a ring of a hard resin fitted on the outer periphery. This modified example substantially corresponds to the configuration shown in FIGS. 6C to 6E described later.

In the comparative example, since the increase in the deflection with respect to the increase in the load is slight, the deformation performance is poor. In the embodiment, the deformation performance is sufficiently large because the deflection increases almost in proportion to the increase in the load. In the modification, the increase in deflection is remarkable with the increase in load, and the deformation performance is extremely large.

FIGS. 6A to 6F are diagrams showing another embodiment of the chain roller according to the present invention. The same components as those in the embodiment shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted. In (a), if lightening holes 51 that do not penetrate at both ends of the chain roller 50 are formed and a rib 52 is provided in the depth of the lightening hole 51, a load acts on the rib 52, so that the thickness is reduced. By changing, the amount of deflection can be adjusted. In (b), if the lightening holes 29 are formed in the chain roller 55 by changing them into circular lightening holes 56, the lightening hole shape is simple, so that the molding is easy and the mold cost is reduced. Can be reduced.

In (c), the chain roller 60 is
A ring-shaped convex portion 62 for preventing lateral displacement of the outer layer roller 61 is provided on the inner surface of the outer layer roller 61 of the hollow cylindrical body, and intermediate layer rollers 63, 63 are attached to both ends of the convex portion 62. The inner layer roller 64 is inserted into the inner layer roller 63, and a hole 65 is opened at the center of the inner layer roller 64.
Are three-layered rollers provided with bearings 26, 27, a collar 31, and washers 67, 67 for integrally holding the respective layers.

In the three-layer roller, the material of each layer can be changed. More specifically, the outer layer roller 61 is made of a hard resin (abrasion-resistant material) having excellent wear resistance to improve durability and extend the life thereof, and the middle layer roller 63 is made of a soft resin having a large energy absorption to absorb impact. 64 is made of a hard resin to maintain the overall shape with respect to the load.

In (d), the chain roller 70 is
A ring-shaped convex portion 72 for preventing lateral displacement of the outer layer roller 71 is provided on the inner surface of the outer layer roller 71, an intermediate layer roller 73 is attached to the convex portion 72, and an inner layer roller 74 is inserted into the intermediate layer roller 73. A hole 7 is formed at the center of the
5 is formed, and concave portions 76, 76 are provided at both ends of the hole 75. The outer roller 71 is made of a hard resin having excellent wear resistance (abrasion resistant material), the intermediate roller 73 is made of a soft resin having large energy absorption, and the inner roller 74 is made of a hard resin. If the respective layers are combined with an adhesive, the two parts (63, 63) of the intermediate layer roller become one part, the number of parts can be reduced, and the washer is reduced, so that the weight and processing cost can be reduced.

In (e), the chain roller 80 is
An intermediate roller 83 is inserted into the outer roller 81, an inner roller 84 is inserted into the intermediate roller 83, a hole 85 is formed at the center of the inner roller 84, and recesses 86, 86 are provided at both ends of the hole 85. It is a thing. The outer layer roller 8
1 is a hard resin (abrasion resistant material) having excellent wear resistance, the intermediate layer roller 83 is made of a soft resin having a large energy absorption, and the inner layer roller 84 is made of a hard resin material. Since the inner surface of the outer layer roller 81 does not have the convex portion 72 shown in (d), the shape is simple. Further, since the intermediate layer roller 83 can be made thicker, the amount of deflection can be increased, and the chain tension can be further reduced.

(F) is a sectional view taken along line ff of (e),
The outer surface of the intermediate roller 83 is adhered to the inner surface of the outer roller 81, and the inner roller 84 is adhered to the inner surface of the intermediate roller 83.
If the outer surfaces are bonded, they do not peel off, so that there is no slip between the layers, and the three layers can act integrally on the load.

FIGS. 7A to 7D are views showing still another embodiment of the chain roller according to the present invention. Note that the same components as those in the embodiment shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted. In (a), if the washers 88, 88 that cover the lightening holes 29 are attached to both ends of the chain roller 22, it is difficult for the running soil to enter the lightening holes 29, so that the amount of deflection is maintained. it can.

(B) is a view taken in the direction of arrow b in (a), and shows a washer 88 which covers all the ten lightening holes 29.
In (c), if a lightening hole 92 that does not penetrate is formed in the end surface of the chain roller 91 and a washer 93 that covers the lightening hole 92 is attached, it is possible to prevent intrusion of earth and sand with one part. The weight can be reduced and the number of parts can be reduced. (D) is a view on arrow d of (c),
Shown are washers 93 that cover all the ten lightening holes 92.

FIGS. 8 (a) to 8 (d) show still another embodiment of the chain roller according to the present invention. The same reference numerals as those in the embodiment shown in FIGS. 2 and 3 denote the same parts. And description thereof is omitted. 2 (a) and FIG. 2 (b) as viewed in the direction of the arrow b, the bearing 2 shown in FIG.
When the needle bearings 6 and 27 are changed to needle bearings 94, the diameters of the washers 94a and 94a are reduced and
Since the area of the end face on which 9 are arranged can be increased, the amount of deflection becomes larger. Energy absorption and relaxation of tension are improved. 2 (c) and FIG. 2 (d) as viewed from the direction of the arrow d, when the bearings 26, 27 in FIG. 2 are replaced with an oil-impregnated collar 95, the diameter of the washer 95a is reduced and the lightening hole 29 is formed. Since the area of the end face to be arranged can be increased, the amount of deflection is further increased. Since the structure is simple, processing costs can be reduced.

The embodiment according to claim 4 is shown in FIGS.
2. An embodiment according to claim 5 will be described with reference to FIG. FIG. 9 is a diagram showing a first modification of the chain roller according to the present invention. In this chain roller structure, a piece 101 is fixed to a vehicle body frame 2 and a swing arm-shaped roller support member 102 is vertically attached to the upper end of the piece 101. Movably mounted, a chain roller 103 is rotatably mounted at the tip of the roller support member 102, and a fixed arm 10 is provided from the body frame 2 substantially parallel to the roller support member 102.
4 is extended, and a compression spring 105 and a buffer mechanism 106 are wrapped around the fixed arm 104 and the roller support member 102. The compression spring 105 may be an elastic body such as rubber. The buffer mechanism 106 is, for example, a cylinder type buffer. Further, the chain roller 103 may be either a hard solid roller or a perforated roller.

When the swing arm 11 descends by a certain amount or more, the chain 14 also descends and hits the chain roller 103. The downward force and the impact force acting at this time are absorbed by the compression of the compression spring 105 and the buffer mechanism 106. That is, when the roller supporting member 102 rotates clockwise, the chain roller 103 is largely displaced downward, and the compression spring 105 and the buffer mechanism 106 can absorb the impact. It should be noted that the compression mechanism 105 may be built into the buffer mechanism 106 and integrated, or the compression mechanism 105 may be replaced with the compression mechanism 105 by omitting the buffer mechanism 106.

FIG. 10 is a view showing a second modification of the chain roller according to the present invention. In this chain roller structure, a piece 111 is fixed to the vehicle body frame 2 and a swing arm-shaped roller support member is provided at the lower end of the piece 111. A chain roller 113 is rotatably mounted on the tip of the roller support member 112, and a fixed arm 114 is extended from the vehicle body frame 2 substantially in parallel with the roller support member 112. And a roller support member 112 and a tension spring 115 and a buffer mechanism 116 are bridged therebetween. Tension spring 11
5 may be an elastic body such as rubber. The buffer mechanism 116 is, for example, a cylinder type buffer. In addition, the chain roller 11
Reference numeral 3 may be a hard solid roller or a perforated roller.

When the swing arm 11 descends by a certain amount or more, the chain 14 also descends and hits the chain roller 113. The downward force and the impact force acting at this time are absorbed by the extension of the tension spring 115 and the buffer mechanism 116. That is, when the roller support member 112 rotates clockwise, the chain roller 113 is largely displaced downward,
The impact can be absorbed by the tension spring 115 and the buffer mechanism 116. In addition, the tension spring 1
Alternatively, the tension spring 115 may be used as a buffer mechanism without the buffer mechanism 116.

FIG. 11 is a diagram showing a third modification of the chain roller according to the present invention. In this chain roller structure, a piece 121 is fixed to the body frame 2 and a swing arm-shaped roller support member is provided at the lower end of the piece 121. A roller 122 is mounted so as to be vertically movable, a chain roller 123 is rotatably mounted on the tip of the roller support member 122, and a tension spring 124 as a buffer mechanism is stretched between the vehicle body frame 2 and the roller support member 122. is there. Tension spring 1
24 may be an elastic body such as rubber. Further, the chain roller 123 may be a hard solid roller or a perforated roller.

When the swing arm 11 descends by a certain amount or more, the chain 14 descends and hits the chain roller 123. The downward force and the impact force acting at this time are absorbed by the extension of the tension spring 125. That is, when the roller supporting member 122 rotates clockwise, the chain roller 123 is largely displaced downward, and the impact can be absorbed by the tension spring 124. Note that the tension spring 12
4 may be replaced with a cylinder type shock absorber integrated with the position of the tension spring 124 in the figure.

FIG. 12 is a view showing a fourth modification of the chain roller according to the present invention. In this chain roller structure, a rotary type shock absorbing mechanism 131 is mounted on the vehicle body frame 2 and a swing arm type roller support is mounted on the shock absorber 131. A member 132 is mounted so as to be vertically movable, and a chain roller 133 is rotatably mounted on the tip of the roller support member 132. The rotary shock absorber 131 is a commercially available rotary damper,
Rubber or a torsion spring may be used, but it is desirable to incorporate a torsion spring for restoration. Also,
The chain roller 133 may be either a hard solid roller or a perforated roller.

When the swing arm 11 descends by a certain amount or more, the chain 14 also descends and hits the chain roller 133. The downward force and the impact force acting at this time are absorbed by the rotary shock absorber 131.

FIG. 13 is a view showing a fifth modification of the chain roller according to the present invention. In this chain roller structure, a block 141 is mounted on the vehicle body frame 2 and
1, a roller support member 142 made of an elastic body (for example, a leaf spring) is vertically movably mounted.
A chain roller 143 is rotatably attached to the end of the second roller. Although the block 141 is merely a mounting member, it may be replaced with a rotary shock absorbing mechanism (131 in FIG. 12). Further, the chain roller 143 may be a hard solid roller or a perforated roller.

When the swing arm 11 descends by a certain amount or more, the chain 14 also descends and hits the chain roller 143. The downward force and the impact force acting at this time are absorbed by the bending of the roller support member 142.

The lightening hole 29 shown in FIG. 3 can also be used as a guide for checking the amount of wear of the roller. When the chain 14 wears the outer surface of the chain roller 22 and reaches the lightening hole 29, it is time to replace the roller 22. Further, the outer layer rollers 61, 7 shown in FIGS.
1, 81 can also be used as a guide for replacement time.

[0044]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect of the invention, the swing arm is mounted on the body frame so as to be vertically movable, the rear wheel is rotatably mounted on the rear portion of the swing arm, and the rear wheel is driven by an engine arranged in front of the swing arm via a chain. In a chain driven vehicle, a chain roller for supporting a chain is mounted on a vehicle body frame side when a rear wheel is lowered by a certain amount or more, so that the chain roller is elastically deformed.

Since the chain roller is configured to be elastically deformed, the displacement and shock absorbing performance can be easily improved, and the structure is simple, and the number of parts can be reduced.

According to a second aspect, the chain roller is a hard rubber or a hard resin roller having a plurality of lightening holes. By forming a plurality of lightening holes in a solid rubber or hard resin solid roller, the deformation performance is dramatically improved. Since the structure is simple, cost can be reduced.

According to a third aspect of the present invention, the chain roller has a wear-resistant material attached to the outer periphery of the soft resin. When the chain hits the chain roller, the soft resin bends to reduce the chain tension. On the other hand, the wear-resistant material prevents wear of the outer peripheral portion. Excessive tension can be reduced and durability can be improved.

A fourth aspect of the present invention is an engine in which a swing arm is mounted on a body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is disposed in front of the swing arm via a chain. In a chain driven vehicle that is driven, a roller support member is vertically movably mounted on the vehicle body frame side, a buffer mechanism is provided between the vehicle body frame side and the roller support member, and the rear wheel descends on the roller support member by a certain amount or more. And a chain roller for supporting the chain when the chain is mounted.

Since the roller supporting member is mounted on the vehicle body frame so as to be vertically movable, a large displacement can be absorbed. Since the shock absorbing mechanism is provided on the roller supporting member, the shock absorbing performance can be enhanced. The number can be reduced.

A fifth aspect of the present invention is an engine in which a swing arm is mounted on a vehicle body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is disposed in front of the swing arm via a chain. In a chain driven vehicle that is driven, a roller supporting member made of an elastic material is attached to the body frame side, and a chain roller that supports the chain when the rear wheel descends by a certain amount or more is attached to the roller supporting member. And

Since the roller supporting member is made of an elastic material,
Displacement and shock absorption performance can be improved, and the structure is simple, and the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle according to the present invention.

FIG. 2 is a plan sectional view of a chain roller structure according to the present invention.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a front view of the chain roller according to the present invention.

FIG. 5 is a graph showing a relationship between a load and a deflection amount of a chain roller.

FIG. 6 is a view showing another embodiment of the chain roller according to the present invention.

FIG. 7 is a diagram showing still another embodiment of the chain roller according to the present invention.

FIG. 8 is a view showing still another embodiment of the chain roller according to the present invention.

FIG. 9 is a diagram showing a first modified example of the chain roller according to the present invention.

FIG. 10 is a diagram showing a second modification of the chain roller according to the present invention.

FIG. 11 is a third modified example of the chain roller according to the present invention.

FIG. 12 is a diagram showing a fourth modification of the chain roller according to the present invention.

FIG. 13 is a fifth modified example of the chain roller according to the present invention.

[Explanation of symbols]

1: motorcycle, 2: body frame, 7: engine, 1
DESCRIPTION OF SYMBOLS 1 ... Swing arm, 12 ... Rear wheel, 13 ... Rear sprocket, 14 ... Chain, 15 ... Drive sprocket, 20
... Chain roller, 22 ... Chain roller, 22a ... Roller, 29 ... Thickening hole, 102, 112, 122, 13
2. Roller support members 103, 113, 123, 13
3, 143: chain roller, 106, 116, 131
... buffer mechanism, 124 ... tension spring as buffer mechanism, 1
42 ... A roller support member made of an elastic material.

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[Procedure amendment]

[Submission date] July 4, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

[0015] Figure 2 is a chain roller structure diagram according to the present invention
FIG. 2 is a view taken in the direction of arrow 2 in FIG.
Is composed of a washer 21, a chain roller 22, a washer 23, and a mounting bolt 24.
Bolt 18 for attaching the link arm 17 to the arm
And attached with mounting bolts 24.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

Chain roller structure diagram according to the present invention; FIG (in FIG. 1
(View from arrow 2)

Claims (5)

[Claims] 1. A swing arm is mounted on a body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is driven by an engine disposed in front of the swing arm via a chain. A chain driven vehicle having a structure in which a chain roller for supporting the chain when the rear wheel is lowered by a certain amount or more is attached to the vehicle body frame, and the chain roller is elastically deformed. Roller structure. 2. The chain roller structure for a chain driven vehicle according to claim 1, wherein said chain roller is a hard rubber or a hard resin roller having a plurality of lightening holes. 3. The chain roller structure for a chain driven vehicle according to claim 1, wherein said chain roller has a wear-resistant material attached to an outer periphery of a soft resin. 4. A swing arm is mounted on a vehicle body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is driven by an engine disposed in front of the swing arm via a chain. In a chain drive vehicle, a roller support member is vertically movably mounted on the vehicle body frame side, and a buffer mechanism is provided between the vehicle body frame side and the roller support member. A chain roller structure for a chain driven vehicle, wherein a chain roller for supporting a chain is mounted. 5. A swing arm is mounted on a vehicle body frame so as to be vertically movable, a rear wheel is rotatably mounted on a rear portion of the swing arm, and the rear wheel is driven by an engine disposed in front of the swing arm via a chain. A chain drive vehicle, wherein a roller supporting member made of an elastic material is mounted on the vehicle body frame side, and a chain roller for supporting the chain when the rear wheel is lowered by a certain amount or more is mounted on the roller supporting member. Chain roller structure for driving vehicles.